In lightweight vehicle applications, it is often desired to produce high starting torque and to ensure variable assistance, whereby electric machines are well suited therefore as opposed to other types of motors or engines. The use of a brushless direct-current (DC) machine is particularly well adapted to these kinds of applications. Some brushless DC machines use a permanent magnet external rotor with three phases of driving coils on the stator core. According to one type of machine, the position of the rotor is sensed with sensors (e.g., Hall effect sensors) and the associated drive electronics. The coils are activated by the drive electronics, based on the detection signals from either the sensors or from the back electromotive force (EMF).
Brushless DC machines are relatively simple in construction, and cost-effective in maintenance in view of their brushless nature. However, there remains a need to produce increasingly efficient brushless DC machines, in a cost-efficient manner. For instance, the weight of the machine components must be minimized, while not affecting the structural integrity of the machine.